رسائل دكتوراة
English
2019
Determination of Some Heavy Metals in Red Sea Igneous Rocks by Atomic Absorption Spectroscopy using Different Sample Treatment Methods
Eiman Ibrahim Balla Ibrahim, Mohamed Osman Babiker , Mustafa Ohag Mohamed
كلية الهندسة والتكنولوجيا-جامعة الجزيرة · السودان
Igneous rocks formed from the cooling of molten rocks comprise the bulk of the crust of the earth. igneous rocks, basalt and granite, are widely distributed in Red Sea Mountains. rocks are composed of different types of minerals. This study aimed to measure the concentration of six heavy metals: Rocks are composed of different types of minerals Iron, Cobalt, Copper, Cadmium, Lead and Silver in basaltic and granitic rocks in the area. The rocks samples, collected from two main stations, were treated using wet and dry digestion by mineral acids- HNO3, H2SO4, HCl, HClO4 and HF. The analyses were performed using Atomic Absorption Spectrophotometry (AAS) which was calibrated by using a series of standard solutions for each element. XRF was used to confirm the results The results shows the concentration for both basaltic and granitic rocks range (mg/kg) of heavy metals obtained by AAS by wet digestion method was found as follows: iron (2.24-229.58), cobalt (1.022 - 12.27), copper (3.34 - 22.82), cadmium (0.04 - 1.78), lead (0.068 - 12.374) and silver (0.533 - 1.96), respectively. The concentration range (mg/kg) for heavy metals by ash digestion method was found for iron (18.022 -123.98), cobalt (1.332 - 11.214), copper (1.98 -33.32), cadmium (0.017 - 3.3), lead (0.80 - 35.167) and silver (0.28 -5.14), respectively. The study demonstrated that the heavy metals concentrations obtained by dry digestion method were highest in rocks samples. However, the literature revealed almost similar findings by using wet and ash digestion methods. Concentration ranges of individual elements were compared with the concentration range obtained from USGS Standard Rocks. The elements under study showed higher concentration than USGS Standard Rocks except for cobalt. The high concentrations of some heavy metals encourages the study of commercial production of these metals in Red Sea Mountains. Qualitative results of XRF were obtained for Fe, Cu and Pb. For basaltic rocks, the range of Fe percent was (20.891-33.629), Cu percent was (0.059-0.081) and Pb percent was (0.015- 0.068). For granitic rocks, the range of Fe percent was (7.148- 16.638 ), Cu percent was (0.026- 0.047 ) and Pb percent was (0.009- 0.059). The X-ray diffraction analysis of the Red Sea rocks revealed that quartz are the major mineral constituents of these rocks. Whereas other minerals like titanite represent considerable constituents in granitic rocks, these might suggest a good potential for economic exploitation of titanium element